a. Field of the Invention
This invention relates to an apparatus for measuring the profile of a moving object. Once the profile of the object has been measured it may be compared against predetermined dimensions, for example to determine whether or not the object has been damaged. The invention is particularly, although not exclusively, used for determining the profile of coiled tubing used in the oil and gas industry, but may also be used for measuring the profile of extruded objects made by a continuous process, or objects in automated transfer lines, or hawser or cable during lifting.
b. Description of the Related Art
A known apparatus for measuring the profile of an object is disclosed in U.S. Pat. No. 4,800,104. It is known to check the internal profile of a tubular member by optically scanning the entire 360.degree. of the surface with a light beam and to receive reflected energy which may be transmitted to electrical energy to provide a trace on a C.R.T. which may then be compared with a predetermined trace. Such an apparatus is mechanically complex and has electronic components requiring electrical power at the measurement station. In an oil and gas well drilling situation a so-called zone 1 permits electrical power, whereas a so-called zone 0 must have no electrical activity to avoid explosions and such a zone 0 station is at the top of a well head.
The present invention seeks to provide an apparatus for measuring the profile of a moving object suitable for use in a zone 0 situation.